Container end closure

ABSTRACT

In a container subjected to internal pressure, a metallic end closure is provided having a central panel portion, a removable portion defined by a score line included in the central panel portion, and an opening tab attached to the removable portion proximate the periphery of the central panel portion, the pull ring or handle of the opening tab being radially inward from the point of attachment of the opening tab to the removable portion. The end closure is additionally provided with means on said central panel portion for releasably holding said opening tab substantially flat against said central panel portion when the central panel portion bulges outwardly due to the internal pressure of the container.

v United States Patent [191.

Hole et al.

[111 3,780,202 Dec. 25, 1973 CONTAINER END CLOSURE [73] Assignee:American Can Company,

Greenwich, Conn.

22 Filed: Apr. 17, 1972 211 App]. No.: 244,777

[52] US. Cl. 220/54 [51] Int. Cl 865d l7/20 [58] Field of Search 220/54,27, 48

[56] References Cited UNITED STATES PATENTS 3,593,875 7/l97l Fraze .r220/54 Primary ExamineF-George T. Hall Att0rney-Robert P. Auber et al.

[ 5 7 ABSTRACT In a container subjected to internal pressure, a metallicend closure is provided having a central panel portion, a removableportion defined by a score line included in the central panel portion,and an opening tab attached to the removable portion proximate theperiphery of the central panel portion, the pull ring or handle of theopening tab being radially inward from the point of attachment of theopening tab to the removable portion. The end closure is additionallyprovided with means on said central panel portion for releasably holdingsaid opening tab substantially flat against said central panel portionwhen the central panel portion bulges outwardly due to the internalpressure of the container.

15 Claims, 5 Drawing Figures PATENIEDDECZS I975 Y 3.780.902

PIC-3.3 6 FIG.5

, l CONTAINER END CLOSURE The present invention relates generally tometallic end closures for easy opening containers. More specifically,the present invention relates to an improved metallic end closure foreasy opening containers of the type having an opening tab attached to aremovable portion of the end closure.

One of the basic developments in the container making industry was thedevelopment of the scored end for an easy opening container, opened bymeans ofa lifting force exerted on an opening tab secured to theremovable portion of the end defined by the score. The most common formof such containers are the beer and beverage cans in which the removableportion defines a comparatively small opening through which the contentsare dispensed when the removable portion is removed from the endclosure. In another form of easy opening container the score line isformed proximate to the periphery of the central panel of'the endclosure to permit the substantially complete removal of the centralpanel. This latter form of container is generally termed the full-open"container and is suitable for use in the packaging of solid-like orchunk-like products, such as processed foods, which are to be removedfrom the container in their entirety. The opening tab for such a fullopen container is usually attached to the removable portion at a pointnear the score line, the pull ring or handle being radially inward fromthe point of at- I tachment of the opening tab to the removable portion.

The point of attachment of the opening tab on end closures havingcomparatively small removable portions may also be proximate to theperiphery of the end with the pull ring radially inward from the pointof attachment. Thus, when the user desires to open the container, thepull ring or handle is grasped and lifted upwardly causing the noseportion of the tab, which acts as a stress concentrator, to initiallybreak or pop the scored section adjacent to it. A pulling force is thenexerted on the pull ring to continue tearing along the score linethereby removing the removable portion from the end. In the case ofcontainers which require sterilization subsequent to the canningoperation, the central panel of the'end closure has a tendency to bulgeoutwardly due to the internal pressure of the container resulting fromthe sterilization process. This outward bulging of the central panel ofthe end closure to which the opening tab is attached causes the free endof the tab, which is radially inward from the point of attachment of thetab to the central panel, to lift away from the central panel of the endclosure. Since the free end of the opening tab of this type ofcontainer, which coincides with the pull ring or handle of the tab, doesnot lie flat against the central panel of the end closure, there existsthe possibility that the pull ring could be inadvertently dislodgedcausing premature opening of the container during the processing andtransportation thereof.

It is, therefore, a primary object of the present invention to providean improved end closure for an easy opening container, wherein theopening tab is attached to the central panel of the end closureproximate the periphery thereof and tehe pull ring is radially inwardfrom this point of attachment, which eliminates in whole or in part thepossibility of accidentally opening the container owing to the liftedfree end of the opening tab.

According to the present invention, this object, and others which willbecome apparent, is accomplished by providing an end closure of the typehaving a central panel portion, a removable portion defined by a scoreline included in said central panel portion, and an opening tab attachedto said removable portion proximate to the periphery of the centralpanel portion, the pull ring or handle of the opening tab being radiallyinward from the point of attachment of the tab to the removable portion,with means for releasably holding the opening tab substantially flatagainst the central panel portion when the central panel portion bulgesoutwardly due to the internal pressure of the container.

The present invention will be described and understood more readily whenconsidered with the embodiments of the accompanying drawings, in which:

FIG. 1 is a plan view of a container end closure according to thepresent invention;

FIG. 2 is an enlarged partial cross-sectional view of the end closure ofFIG. 1 taken along line 2-2 of FIG.

FIG. 3 is a plan view of the opening tab of the end closure of FIG. 1;

FIG. 4 is a plan view of a modified form of the end closure of FIG. 1;and

FIG. 5 is an enlarged partial cross-sectional view of the end closure ofFIG. 4 taken along line 55 of FIG.

Now referring to the drawings, there is shown in FIG. 1 an end closure,generally designated 10, for an easy opening container of the full-openend type. End closure 10 maybe circular and constructed of steel,aluminum, tin plate, plastic, or other suitable repturable material. Asclearly seen, end closure 10 is formed'with a generally planar centralpanel portion, generally designated 12, which merges at its peripherywith annular countersink wall 14. The upper end portion of wall 14merges with outwardly extending curled flange 16 which may beinterfolded with the end flange of a container body (not shown) to forman end seam (not shown).

Included in central panel 12 is a removable portion, generallydesignated 18, which is defined by and included within score line 20.Removable portion 18 becomes detached from end closure 10 when score 20is completely ruptured. The entire length of score line 20 may beproximate to the periphery of central panel 12 thereby making removableportion 18 substantially coextensive with the central panel.

In order to rupture score 20 and detach removable portion 18 from endclosure 10, an opening tab,.generally designated 22, is provided.Opening tab 22 is attached to the removable portion proximate theperiphery of central panel 12 by a suitable securing means such ashollow rivet 24 which may be integral with and formed in removableportion 18.

As clearly seen, opening tab 22 includes 'a web portion 26, a handleportion or pull ring 28 attached to web portion 26, and a stressconcentrating nose portion 30 formed in web portion 26 and oppositelydisposed from pull ring 28. Opening 32 is provided in web portion 26 forthe purpose of accepting rivet 24 for the attachment of opening tab 22to removable portion 18. In this manner rivet 24 functions as a fulcrumfor opening tab 22 such that when pull ring 28 is'lifted upwardly tab 22pivots about rivet 24 causing nose portion 30 to contact score line 20and concentrate the stress at the point of contact thereby breaking thescore. Handle portion or pull ring 28, although shown in the drawings asbeing in the form of a ring may have any suitable shape or configurationdesired, such as rectangular, triangular, etc. The handle portion isadapted for ease of grasping by the user, such as by the insertionthrough the ring of at least one of the users fingers. A flattenedportion, generally designated 34, may be provided at that portion ofpull ring 28 which is to be initially lifted by the user for the purposeof permitting easier insertion of the users finger. Inwardly angularlyflattened portions, generally designated 36 and 38, of pull ring 28 areprovided having inwardly extending arcuate projections, respectivelydesignated 40 and 42, as most clearly seen in FIG. 3.

As hereinbefore noted with respect to containers which are sterilizedsubsequent to the canning operation, the central panel of the endclosure tends to bulge outwardly due to the internal pressure within thecontainer resulting from the sterilization process. Such a condition ismost clearly depicted in FIG. 2 where central panel 12 is arcuate inshape having the smallest deflection at its periphery and the maximumdeflection at its center.

Since the point of attachment of opening tab 22 is proximate to theperiphery of central panel 12, where a small amount of end deflectionoccurs, the free portion of tab 22 which is radially inward from rivet24 would be displaced upwardly with respect to central panel 12. Inorder to prevent'this upward displacement of the free portion of openingtab 22, protuberances 44 and 46 are provided on central panel 12. Protuberances 44 and 46 are so positioned that they lie within pull ring28 adjacent the inner edge 48 of the pull ring and proximate to theflattened portions 36 and 38 thereof. The sides of protuberances 44 and46 adjacent projections 40 and 42 are substantially flat with the upperportions thereof extending slightly over projections 40 and 42 when pullring 28 lies flat against central panel 12, as clearly seen in FIG. 2.Due to the arcuate shape of projections 40 and 42 there results a pointcontact between the projections and the respective protuberances whichpermits the pull ring to be disengaged from 'the protuberances withrelative ease. Protuberances 44 and 46 may be formed in central panel 12by suitable dimple forming dies simultaneously with the formation ofrivet 24 and are preferably hemispherical in shape. The flattened sidesof protuberances 44 and 46 are formed by flattening the portions thereofwith suitable dies and due to the spring back of the stretched upperportions of the protuberances these upper portions extend outwardly overthe flattened sides when the die is removed.

A slightly modified form of the present invention is seen in FIGS. 4 and5 where the reference numerals indicating parts similar to the partsdesignated in FIGS. 1-3 are preceded by the numeral 1. The differencebetween the embodiments lies in the shape of the respectiveprotuberances. As clearlyseen in the drawings protuberances 144 and 146are formed similarly to protuberances 44 and 46 with the added featurethat they are angularly flattened at 150 and 152 thereby resulting in agreater overlapping of pull ring 128.

It is understood that the foregoing general and detailed descriptionsare explanatory of the present invention and are not to be interpretedas restrictive of the scope of the following claims. 3

'What is claimed is:

1. An improved end closure for a container subjected to internalpressure of the type having a central panel portion, a removable portiondefined by a score line included in said central panel portion, and anopening tab including a pull ring attached to said removable portion forremoval thereof by the user, the point of attachment of said opening tabto said removable portion being proximate the periphery of said centralpanel portion with the pull ring of said opening tab radially inwardfrom the point of attachment, wherein the improvement comprises means onsaid central panel portion releasably engaging the pull ring of saidopening tab to thereby hold said opening tab substantially flat againstsaid central panel portion when said central panel portion bulgesoutwardly due to the internal pressure of the container. 2. The improvedend closure as defined in claim 17 wherein the means for releasablyengaging the pull ring of said opening tab comprises at least oneprotuberance on said central panel portion adjacent the pull ring ofsaid opening tab, said protuberance having an upper portion whichpartially overlapps said pull ring when said pull ring is pressed ontosaid central panel portion thereby releasably holding said opening tabsubstantially flat against said central panel portion when said centralpanel portion bulges outwardly due to the internal pressure of thecontainer.

3. The improved end closure as defined in claim 1 wherein the means forreleasably engaging the pull ring of said opening tab comprises a firstprotuberance on said central panel portion adjacent the pull ring ofsaid opening tab and a second protuberance on said central panel portionadjacent the pull ring of said opening tab, said first and secondprotuberances having upper portions which partially overlap said pullring when said pull ring is pressed onto said central panel portionthereby releasably holding said opening tab substantially flat againstsaid central panel portion when said central panel portion bulgesoutwardly due to the internal pressure of the container.

- 4. The improved end closure as defined in claim 3 wherein said firstand second protuberances are so positioned on said central panel portionas to be within the pull ring of said opening tab.

5. The improved end closure as defined in claim 3 wherein said first andsecond protuberances are raised dimples on said central panel portionwhich protrude above the plane defined by said central panel portion. 6.The improved end closure as defined in claim 5 wherein said raiseddimples are hemispherical in shape having the sides adjacent said p ullring substantially flat.-

7. The improved end closure as defined in claim 6 wherein the portionsof said pull ring adjacent the flat sides of said raised dimples aresubstantially flat having arcuate projections extending toward saiddimples whereby point contact is made between said projections and theflat sides of said dimples when said pull ring is pressed onto saidcentral panel portion.

8. The improved end closureas 'defined in claim '6 wherein saidhemispherically shaped raised dimples are angularly flattened therebyextending the upper portions of the flat sides of the dimples partiallyover said pull ring.

9. The improved end closure as defined in claim 1 wherein said endclousre is metallic.

10. The improved end closure as defined in claim 1 wherein said endclosure is plastic.

11. An end closure for a container subjected to internal pressure whichcomprises a central panel portion, a removable portion defined by ascore line included in said central panel portion, an opening tabattached to said removable portion, the point of attachment of saidopening tab to said removable portion being proximate to the peripheryof said central panel portion, the pull ring of said opening tab beingradially inward from the point of attachment of said opening tab to saidremovable portion, a first hemispherically shaped dimple on said centralpanel portion within the pull ring of said opening tab, and a secondhemispherically shaped dimple on said central panel portion within thepull ring of said opening tab, the sides of said first and seconddimples adjacent the inner edge of the pull ring being substantiallyflat and having upper portions extending slightly over said pull ringwhen said pull ring is pressed onto said central panel portion tothereby releasably engage the pull ring of said opening tab andreleasably hold said opening tab substantially flat against said centralpanel portion when said central panel portion bulges outwardly due tothe internal pressure of the container.

12. The end closure as defined in claim 11 wherein said removableportion defined by said score line is substantially co-extensive withsaid central panel porsaid end closure is plastic.

1. An improved end closure for a container subjected to internalpressure of the type having a central panel portion, a removable portiondefined by a score line included in said central panel portion, and anopening tab including a pull ring attached to said removable portion forremoval thereof by the user, the point of attachment of said opening tabto said removable portion being proximate the periphery of said centralpanel portion with the pull ring of said opening tab radially inwardfrom the point of attachment, wherein the improvement comprises means onsaid cEntral panel portion releasably engaging the pull ring of saidopening tab to thereby hold said opening tab substantially flat againstsaid central panel portion when said central panel portion bulgesoutwardly due to the internal pressure of the container.
 2. The improvedend closure as defined in claim 17 wherein the means for releasablyengaging the pull ring of said opening tab comprises at least oneprotuberance on said central panel portion adjacent the pull ring ofsaid opening tab, said protuberance having an upper portion whichpartially overlapps said pull ring when said pull ring is pressed ontosaid central panel portion thereby releasably holding said opening tabsubstantially flat against said central panel portion when said centralpanel portion bulges outwardly due to the internal pressure of thecontainer.
 3. The improved end closure as defined in claim 1 wherein themeans for releasably engaging the pull ring of said opening tabcomprises a first protuberance on said central panel portion adjacentthe pull ring of said opening tab and a second protuberance on saidcentral panel portion adjacent the pull ring of said opening tab, saidfirst and second protuberances having upper portions which partiallyoverlap said pull ring when said pull ring is pressed onto said centralpanel portion thereby releasably holding said opening tab substantiallyflat against said central panel portion when said central panel portionbulges outwardly due to the internal pressure of the container.
 4. Theimproved end closure as defined in claim 3 wherein said first and secondprotuberances are so positioned on said central panel portion as to bewithin the pull ring of said opening tab.
 5. The improved end closure asdefined in claim 3 wherein said first and second protuberances areraised dimples on said central panel portion which protrude above theplane defined by said central panel portion.
 6. The improved end closureas defined in claim 5 wherein said raised dimples are hemispherical inshape having the sides adjacent said pull ring substantially flat. 7.The improved end closure as defined in claim 6 wherein the portions ofsaid pull ring adjacent the flat sides of said raised dimples aresubstantially flat having arcuate projections extending toward saiddimples whereby point contact is made between said projections and theflat sides of said dimples when said pull ring is pressed onto saidcentral panel portion.
 8. The improved end closure as defined in claim 6wherein said hemispherically shaped raised dimples are angularlyflattened thereby extending the upper portions of the flat sides of thedimples partially over said pull ring.
 9. The improved end closure asdefined in claim 1 wherein said end clousre is metallic.
 10. Theimproved end closure as defined in claim 1 wherein said end closure isplastic.
 11. An end closure for a container subjected to internalpressure which comprises a central panel portion, a removable portiondefined by a score line included in said central panel portion, anopening tab attached to said removable portion, the point of attachmentof said opening tab to said removable portion being proximate to theperiphery of said central panel portion, the pull ring of said openingtab being radially inward from the point of attachment of said openingtab to said removable portion, a first hemispherically shaped dimple onsaid central panel portion within the pull ring of said opening tab, anda second hemispherically shaped dimple on said central panel portionwithin the pull ring of said opening tab, the sides of said first andsecond dimples adjacent the inner edge of the pull ring beingsubstantially flat and having upper portions extending slightly oversaid pull ring when said pull ring is pressed onto said central panelportion to thereby releasably engage the pull ring of said opening taband releasably hold said opening tab substantially flat against saidcentral panel portion when said central Panel portion bulges outwardlydue to the internal pressure of the container.
 12. The end closure asdefined in claim 11 wherein said removable portion defined by said scoreline is substantially co-extensive with said central panel portion. 13.The end closure as defined in claim 11 wherein said pull ring furthercomprises substantially flat portions adjacent the flat sides of saiddimples and arcuate projections extending toward said dimples from saidflat portions whereby point contact is made between said projections andthe flat sides of said dimples.
 14. The end closure as defined in claim11 wherein said end closure is metallic.
 15. The end closure as definedin claim 11 wherein said end closure is plastic.